Letta's comments Monday, during a trip to Doha, Qatar, come amid an online campaign by the anti-establishment 5 Star Movement against the speaker of Parliament's lower house.

A video posted on the popular blog of the 5-Star Movement's founder, Beppe Grillo, depicts Laura Boldrini as a paper cutout who wears a communist symbol, then a fascist black shirt. Boldrini told state TV Sunday that comments accompanying the video were full of "sexual violence."

Hannes Swoboda, the European parliament's center-left opposition leader, has denounced Grillo and his followers for their "racist, sexist and rape-glorifying online exchange" about Boldrini.

Grillo supporters also in recent days have attacked a TV interviewer and have long railed against Italy's president.